This is a question I also would like answered. I have tried the offered fix and it still shows up on my pages. I also went to the linked pages here and still see it.
While I do subscribe to the theory "If you do not want everyone to see it do not post it on the internet" It would be nice to make it a bit more difficult to link to Facebook.
I have checked the "hide" button for slideshow and share in most of my galleries but it is still showing the button when you view an image. Without being logged in.
Any other suggestions please? I guess waiting till after the update is an option, maybe then can deselect that option.